Packaging device

ABSTRACT

A packaging device, particularly for vacuum packaging, and particularly for packaging trays containing food products, which comprises a heat-sealing and cutting station for heat-sealing a film on the edge of a tray and for cutting the film, the device further comprising a supporting surface that comprises a plurality of receptacles that accommodate a plurality of dies which can have different dimensions and/or formats in order to accommodate trays of different dimensions and/or formats, the supporting surface being actuatable in order to move one of such dies at the heat-sealing and cutting station.

The present invention relates to a packaging device, particularly forvacuum packaging, and particularly for packaging trays containing foodproducts or the like.

Currently in the sector of packaging food trays, heat-sealing machinesare known which perform, generally in vacuum bells or in a controlledatmosphere, the heat-sealing of a film on the edge of a tray containingthe food product and then trim the film that has been heat-sealed on theedge of the tray, by way of a die punch or other cutting means. In theabove heat-sealing operation, the tray is usually accommodated in alower die, and an upper heat-sealing plate, with substantially identicalshape and dimensions to those of the tray to be heat-sealed, is broughtproximate to and pressed against the edges of the tray, so that the filminterposed between the tray and the upper plate is heat-sealed at theedges of the tray.

Such conventional machines are not devoid of drawbacks, including firstof all the fact that they are dedicated machines for a specific type oftray, in terms of dimensions and/or format, and therefore are difficultto modify. In particular, in order to be able to work on trays ofdifferent dimensions and/or formats it is necessary for an operator tointervene and substitute at least the lower die, and usually theheat-sealing plate as well, in order to be able to adapt it to thespecific tray being processed.

Such conventional machines are therefore rather inflexible in use.Furthermore, the complex substitution, performed by hand, of the die andof the heat-sealing plate requires an extended machine shutdown, whichentails unwanted increases in cost.

The aim of the present invention consists in providing a packagingdevice that overcomes the limitations of the known art, by making itpossible to process food trays of various different formats and/ordimensions.

Within this aim, an object of the present invention is to provide apackaging device that is particularly simple in operation, and which canbe used by an operator with no special training.

Another object of the invention consists in providing a packaging devicethat makes it possible to avoid unwanted machine shutdowns and “dead”times for the substitution of the die and of the heat-sealing plate.

Another object of the invention consists in providing a packaging devicethat is capable of offering the widest guarantees of reliability andsafety in use.

This aim and these and other objects which will become better apparenthereinafter, are achieved by a packaging device, comprising aheat-sealing and cutting station for heat-sealing a film on the edge ofa tray and for cutting said film, characterized in that it comprises asupporting surface that comprises a plurality of receptacles thataccommodate a plurality of dies, said dies having different dimensionsand/or formats in order to accommodate trays having different dimensionsand/or formats, said supporting surface being actuatable in order tomove one of said dies at said heat-sealing and cutting station.

Further characteristics and advantages of the invention will becomebetter apparent from the detailed description of a preferred, but notexclusive, embodiment of a packaging device, which is illustrated by wayof non-limiting example with the aid of the accompanying drawingswherein:

FIG. 1 is a perspective view of an embodiment of a packaging device,according to the invention;

FIG. 2 is a perspective view of some components only of the packagingdevice shown in FIG. 1;

FIG. 3 is a sectional side view of the packaging device shown in FIG. 1,in a configuration for beginning work;

FIG. 4 is an enlarged detail of part of FIG. 3;

FIG. 5 is a sectional side view of the packaging device shown in FIG. 1,in a configuration for generating the vacuum;

FIG. 6 is a sectional side view of the packaging device shown in FIG. 1,in a configuration for heat-sealing and cutting;

FIG. 7 is an enlarged detail of part of FIG. 6;

FIG. 8 is a sectional side view of the packaging device shown in FIG. 1,provided with a measurement station;

FIG. 9 is a view from above of the measurement station shown in FIG. 8;

FIG. 10 is a front elevation view of the measurement station shown inFIG. 8;

FIG. 11 shows a die belonging to the heat-sealing and cutting station ofthe packaging device, according to the invention;

FIGS. 12 and 13 show the die in FIG. 11, in a side elevation view, intwo different working positions.

With reference to the figures, the packaging device, generallydesignated by the reference numeral 1, comprises a heat-sealing andcutting station 3 for heat-sealing a film 5 on the edge of a tray 7, andfor cutting the film 5, once heat-sealed to the edge of the tray 7.

According to the invention, the packaging device 1 comprises asupporting surface 9 that comprises a plurality of receptacles 11 thataccommodate a plurality of dies 13. The dies 13 can have differentdimensions and/or formats in order to accommodate trays 7 of differentdimensions and/or formats. The supporting surface 9 is actuatable inorder to move one of the dies 13 at the heat-sealing and cutting station3. In this manner, at the heat-sealing and cutting station 3, the tray 7is accommodated in the corresponding die 13 for the execution of theoperations of heat-sealing and cutting the film 5.

Advantageously, the supporting surface 9 can be a rotating table, therotation of which is such as to place one of the dies 13 at theheat-sealing and cutting station 3. In particular, as illustrated in theaccompanying figures, the rotatable supporting surface 9 comprises threereceptacles 11, one for each die 13. The rotation of the supportingsurface 9 therefore makes it possible to place a designated die 13 atthe heat-sealing and cutting station 3.

The packaging device 1 can comprise means 31 for conveying the trays 7from a station for feeding the trays 7 to the die 13 that isaccommodated in the supporting surface 9 that is arranged at theheat-sealing and cutting station 3.

The conveyor means 31 comprise rods 35, which are advantageouslyactuated by a motorized chain 37 and are adapted to slide over a sheetmetal surface 39. The trays 7 are pushed by the rods 35 along the sheetmetal surface 39 to the heat-sealing and cutting station 3 where thecorrect die 13 is already arranged. In particular, the sheet metalsurface 39, which is arranged at a height that is greater than that atwhich the die 13 is arranged at the heat-sealing and cutting station 3,comprises a hole that faces the die 13. In this manner, the tray 7 ispushed by the rods 35 into the hole and falls into the die 13.

Furthermore the packaging device 1 can comprise a station 15 formeasuring the dimensions and/or format of the tray 7, arranged upstreamof the heat-sealing and cutting station 3, as shown in FIGS. 8, 9 and10.

The detection of the extent of the dimensions and/or format of the tray7 determines the selection of one of the dies 13, so that thepreselected die 13 is placed at the heat-sealing and cutting station 3.The preselected die 13, once at the heat-sealing and cutting station 3,will receive the corresponding tray 7 for the execution of theoperations of heat-sealing and cutting of the film 5, as explainedhereinafter. In the measurement station 15 there are advantageouslysensor means 41 that are adapted to measure the dimensions of the tray7.

The measurement station 15 advantageously comprises centering means 33for centering the tray 7 with respect to the corresponding die 13. Thecentering means 33 can comprise a pair of centering elements 43, whichare arranged at the sides of the tray 7. The centering elements 43 aremoved by a motor 45 that actuates a toothed wheel, which moves a pair oftoothed racks 47 with which the centering elements 43 are connected.

The sensor means 42 advantageously comprise a laser/photocell pairingand can be advantageously connected to the centering elements 43, sothat the operations of centering and measuring the tray 7 are performedsubstantially simultaneously. The measurement of the tray 7, in termsboth of width and of length, makes it possible to select the correct die13, to determine the length of the advancement of the rods 35 in orderto ensure that the tray 7 falls correctly into the hole present in thesheet metal surface 39, thus taking up position correctly in the die 13,and to determine the length of the advancement of the film 5 to beunwound in order to completely cover the tray 7, while limiting needlesswaste of the film 5.

The heat-sealing and cutting station 3 advantageously comprises a vacuumbell 17 that comprises, internally, heat-sealing means 19 and cuttingmeans 21 of the film 5. Furthermore, the vacuum bell 17 is adapted tocontain one of the dies 13, and in particular the die 13 that is in eachinstance arranged in the heat-sealing and cutting station 3.

In particular, the vacuum bell 17 is defined by an upper chamber 23 andby a lower chamber 24, which can be locked by mutual superimposition.The lower chamber 24 is at least partially defined in the supportingsurface 9. In particular, there is a lower chamber 24 for each die 13,while there is one single upper chamber 23 at the heat-sealing andcutting station 3. The rotation of the supporting surface 9 is in factadapted to place not just the die 13, but also the corresponding lowerchamber 24, at the heat-sealing and cutting station 3.

Advantageously the heat-sealing means 19 are connected kinematically tocutting means 21 for cutting the film 5, so that the movement of theheat-sealing means 19 determines the actuation of the cutting means 21.Preferably the heat-sealing means 19 comprise a heat-sealing plate 25that is adapted to come into abutment against the film 5 in order toheat-seal it on the edges of the tray 7.

Each die 13 further comprises a surface 49 that can move vertically andis adapted to support the tray 7, and to move the tray 7 vertically, asdescribed hereinafter.

The packaging device 1 advantageously comprises lever means 27 adaptedto connect kinematically the movement of the above mentionedheat-sealing means 19, and specifically of the heat-sealing plate 25, tothe actuation of the cutting means 21, so that the descent of theheat-sealing plate 25 determines the rise of the cutting means 21 beyondthe heat-sealing surface 29 and the consequent cutting of the film 5.

As shown in FIGS. 4, 7, 11, 12 and 13, the cutting means 21 comprise atleast one blade 51, which runs around the entire perimeter of the die13. The lever means 27 comprise a lever 53 pivoted with respect to afulcrum 55 which is integral with the supporting surface 9. The lever 53comprises, at a first end 57, a first slot 59, and, at a second end 61,a second slot 63. The first slot 59 engages with a first pivot 65, whichis integral with the blade 51, while the second slot 63 engages with asecond pivot 67, which is integral with a perimetric frame 69 which isexternal to the die 13. Lowering the perimetric frame 69 entails, by wayof the above mentioned lever means 27, raising the blade 51. As is clearfrom FIG. 7, lowering the perimetric frame 69 is done by way of thepressure that the heat-sealing plate 25 exerts, by way of its outer rim71, on the perimetric frame 69 proper. Furthermore, the perimetric frame69, or the outer rim 71 of the heat-sealing plate 25, or both, cancomprise a rubber element 73, which helps to lock the film 5 in placeduring the raising of the blade 51 and the consequent cutting of thefilm 5. When the heat-sealing plate 25 stops exerting the pressingaction on the perimetric frame 69, by way of the springs 75 it tends toreturn to its inactive, raised position, and consequently the blade 51descends below the heat-sealing surface 29.

The dies 13 are advantageously replaceable if necessary. In fact eachreceptacle 11 defined in the supporting surface 9 can accommodate dies13 of different dimensions and/or formats.

Operation of the packaging device 1 is as follows.

The trays 7 are fed, by a feeding station, not shown, to the sheet metalsurface 39 and are pushed by the rods 35 toward the measurement andcentering station 15, where the measurements of the tray 7 are taken, soas to select, from among the dies 13 present in the supporting surface9, the correct one for the specific tray 7, and thus place it at theheat-sealing and cutting station 3, by way of the rotation of thesupporting surface 9. At the same time, on the basis of the measurementof the tray 7, the rods 35 are made to advance so as to push the tray 7to the center of the preselected die 13 and the necessary length of film5 is unwound to cover the upper opening of the tray 7.

Once the selected die 13, with the corresponding lower vacuum chamber24, is arranged in the heat-sealing and cutting station 3, the tray 7 ismade to advance so as to be arranged on the movable surface 49.

The film 5 is conveniently made to slide under the upper vacuum chamber23.

At this point, the upper vacuum chamber 23 is lowered, closing onto thelower chamber 24, and, in its lowering, also moving the film 5, whichcomes up against the opening of the tray 7 to be covered. By way of thevacuum ducts 77 and 79 the vacuum bell 17, defined by the two chambers23 and 24 which are now hermetically tight, is placed under a vacuum, asillustrated in FIG. 5. Through the vacuum ducts 77 and 79 it is alsopossible to send adapted gases that are adapted to maintain the content,generally food, of the trays 7. The upper chamber 23, the lower chamber24, and the internal volume of the tray 7 are all affected by the vacuumor gases.

The movable surface 49 is lowered vertically, leaving the tray 7resting, by way of its lateral edges 81, on a supporting frame 83 of thetray 7 which is defined in the die 13.

Once the conditions of vacuum have been created, the heat-sealing plate25 descends toward the film 5, so that the innermost portion 85 of theheat-sealing plate 25 comes into abutment against the edge 81 of thetray 7, supported by the supporting frame 83, with the film 5interposed, so that the film 5 is heat-sealed to the edges of the tray7.

At the same time, the heat-sealing plate 25 impacts on the rubberelement 73 of the perimetric frame 69, defeating the elastic forceexerted by the springs 75, and actuating the lever means 27 so that thefurther descent of the perimetric frame 69 causes the rising of theblade 51 and thus the cutting of the film 5, which in the meantime iskept in place by the rubber elements 73.

Once the heat-sealing and the cutting of the film 5 are complete, theupper chamber 23 ascends upwardly, taking the heat-sealing plate 25 withit. The movable surface 49 rises vertically, and lifts the tray 7, whichhas just been sealed, so as to detach it from the supporting frame 83and bring it to a position that enables it to be pushed out from theheat-sealing and cutting station 3 by way of the thrust impressed by therods 35.

In practice it has been found that the packaging device, according tothe present invention, achieves the intended aim and objects in that itmakes it possible to process food trays of various different formatsand/or dimensions.

Another advantage of the packaging device, according to the invention,consists in that it is capable of automatically recognizing thedimensions and/or the format of the trays, in order to select thecorrect die.

Another advantage of the device, according to the invention, consists inthat it requires a vacuum bell of limited size.

Another advantage of the device, according to the invention, consists inthat it makes it possible to easily change the dies, so as to render themachine flexible for use with various types of trays.

Another advantage of the device, according to the invention, consists inthat it reduces the waste of film, in that it has a measurement stationthat is capable of establishing the exact length of film to be unwound,on the basis of the dimensions and/or the format of the tray.

Another advantage of the device, according to the invention, consists inthat it is substantially mechanical, and is therefore more reliable.

The packaging device, thus conceived, is susceptible of numerousmodifications and variations, all of which are within the scope of theappended claims.

Thus, for example, it is possible that the dies be moved in arectilinear direction instead of being moved along a circular path. Inthis case the supporting surface would be a linear element instead of arotating table.

Moreover, all the details may be substituted by other, technicallyequivalent elements.

In practice the materials employed, provided they are compatible withthe specific use, and the contingent dimensions and shapes, may be anyaccording to requirements.

The disclosures in Italian Patent Application No. MI2013A002079 fromwhich this application claims priority are incorporated herein byreference.

Where technical features mentioned in any claim are followed byreference signs, those reference signs have been included for the solepurpose of increasing the intelligibility of the claims and accordingly,such reference signs do not have any limiting effect on theinterpretation of each element identified by way of example by suchreference signs.

1-10. (canceled)
 11. A packaging device, comprising a heat-sealing andcutting station for heat-sealing a film on an edge of a tray and forcutting said film, and comprising a supporting surface that comprises aplurality of receptacles that accommodate a plurality of dies, said dieshaving different dimensions and/or formats in order to accommodate trayshaving different dimensions and/or formats, said supporting surfacebeing actuatable in order to move one of said dies at said heat-sealingand cutting station.
 12. The packaging device according to claim 11,wherein said supporting surface is a rotating table, the rotation ofsaid rotating table placing one of said dies at said heat-sealing andcutting station.
 13. The packaging device according to claim 11, furthercomprising a measurement station for measuring dimensions and/or formatof said tray, arranged upstream of said heat-sealing and cuttingstation, the detection of the measurement of the dimensions and/or ofthe format of said tray causing the selection of one of said dies. 14.The packaging device according to claim 11, wherein said heat-sealingand cutting station comprises a vacuum bell, which comprisesheat-sealing means and means for cutting said film, said vacuum bellbeing adapted to contain one of said dies.
 15. The packaging deviceaccording to claim 14, wherein said vacuum bell is defined by an upperchamber and a lower chamber, which can be locked by mutualsuperimposition, said lower chamber being at least partially defined insaid supporting surface.
 16. The packaging device according to claim 14,wherein said heat-sealing means are adapted to abut against said film inorder to heat-seal said film on the edges of said tray, saidheat-sealing means being connected kinematically to cutting means forcutting said film, so that the movement of said heat-sealing meanscauses the actuation of said cutting means.
 17. The packaging deviceaccording to claim 16, further comprising lever means adapted to connectkinematically said heat-sealing means to said cutting means, so that adescent of said heat-sealing means causes a rise of said cutting meansbeyond the heat-sealing surface and the cutting of said film.
 18. Thepackaging device according to claim 11, further comprising means forconveying said trays from a station for feeding said trays to said dieaccommodated in said supporting surface located at said heat-sealing andcutting station.
 19. The packaging device according to claim 13, whereinsaid measurement station comprises centering means for centering saidtray with respect to the corresponding die.
 20. The packaging deviceaccording to claim 11, wherein said dies are replaceable if necessary.